The quote that I gave as a challenge was from The Problem of Pain by Clive Staples Lewis, Chapter 3, third paragraph (not counting the chapter's leading quotation.) In the printing I have, it appears on pages 28 and 29.
I am a skeptic. There is very little that I believe uncritically. <I exist. Other minds exist. My perceptions are generally meaningful and useful (they can successfully predict actions likely to lead to other perceptions.) Pleasure good; pain bad (this applies to other minds as well.)> Pretty much anything else, I will consider what it would mean if it were not true, even if I personally believe it to be true.